1. Field of the Invention
The present invention generally relates to a pest monitoring device and method of sensing said pests arriving in traps set for the purpose of beetle monitoring. More particularly the present invention relates to a beetle sensing device providing greater sensitivity, greater sensing consistency, and reduced clogging risk as well as means of remotely recording data from both individual sensing devices and a plurality of said devices connected via a network.
2. Description of the Related Art
Pest monitoring is an established management tool to help protection crops, forests, and gardens against damage done by various pests including for example, beetles. Several beetle species which are pests of concern include the Bark beetles that attack conifers. Damage to, and death of, these conifers is done by these beetles burrowing in their bark. Particularly susceptible to attack are stressed trees. In the western U.S. and Canada conifers are presently under severe attack by the mountain pine beetle.
Ambrosia beetles feed on wood in various forms, including for example, live fruit and nut trees as well as on seasoning logs and/or lumber leaving pinholes which reduce the value of the lumber. As such they pose an economic threat to lumberyards.
The Japanese beetle is a truly vexing pest. The larvae feed on a broad variety of roots and the adults feed on the leaves of more than 250 important plants such as turf grasses, crops, ornamental plants, and vegetables. They presently infest the U.S. east of the Mississippi River. In addition, the risk of additional invasive beetle pest arrival is increasing as international commerce increases.
In response to such pest threats pest traps are used for manual monitoring of pest movement and population. Beetle traps are well known as a management tool to combat pest damage to agricultural, horticultural, forest and lumber resources. For example, U.S. Pat. No. 4,471,563 issued Sep. 18, 1984 to Lindgren teaches a trap for catching bark beetles and ambrosia beetles. Likewise, U.S. Pat. No. 2,020,283 issued May 10, 1935 to Armstrong et al teaches a trap for Japanese beetles.
More recently there have been efforts to automate the monitoring of pest traps including beetle traps as well as providing the ability to network a desired number of traps allowing for automated management of a plurality of traps connected into a single network. For example, U.S. Pat. No. 5,646,404 issued Jul. 8, 1997 to Litzkow et al, teaches a wired network monitoring system for a plurality of pest traps used in stored products. The traps in this teaching utilize light beam interruption for insects infesting stored grain products.
Similarly, U.S. Pat. No. 6,882,279 issued Apr. 19, 2005 to Shuman, et al, teaches the use of a wireless network monitoring system for a plurality of pest traps used in stored products using variously directed multiple beams to size the trapped insects.
U.S. Pat. No. 6,766,251 issued Jul. 20, 2004 to Mafra-Neto, et al, teaches a wireless network monitoring system for a plurality of pest traps to monitor arbitrary agricultural pests using arbitrary sensors.
All of these related art references utilize transmissive optical sensing having sensing passageways for falling pests between an LED emitter and a photo detector sensor which is located near the boundaries of, and horizontally and diametrically opposed across a section of the passageway. An arriving pest breaks a beam radiated by the emitter, casting a shadow upon the photo-detector sensor. Relative to the unobstructed no pest condition, the change in radiation incident upon the photo-detector sensor due to shadowing by the pest governs sensitivity to pest arrivals. Optical spreading between the emitter, the sensor, and the pest determines the difference in incident radiation between unobstructed and shadowed conditions, and sensitivity depends on pest location within the passageway section. The passageway section is sized to be just larger than the pest to maximize sensitivity and to minimize sensitivity variations from pest location within the passageway.
One limitation of devices utilizing transmissive optics is that they are susceptible to clogging and therefore poorly suited to outdoor applications in which debris and predators are likely to enter and clog the narrow passageways, thereby preventing sensing of subsequently arriving pests. Additionally clogging necessitates the manual clearing of the device to recover monitoring function. The labor of visiting monitoring devices for clog removal greatly reduces the value and application of automated remote pest monitoring. In these related art references increasing the passageway size is the means of preventing such clogging. However passageway enlargement introduces at least two undesirable results. First system sensitivity decreases because of the increased optical spreading over increased distances between the emitter and the sensor, and second variation of sensor response increases with the increased extent of possible pest locations within the passageway section. While in the first case system sensitivity can be recovered to some extent with a more energetic emitter or a larger sensor, these approaches increase both component costs and energy consumption. However in applications where line power is unavailable, and energy must be provided by batteries, increasing the energy demand limits the use and usability of remote pest sensing devices. The latter issue of inconsistent sensitivity complicates definition of the pest arrival threshold, which must be established and embedded in system electronics, by reducing the repeatability and reliability of pest sensing.
The compromise required in these teachings between sensitivity, sensing zone size, and sensing uniformity is undesirable because an accurate and useful beetle monitor would optimize all three attributes. However, in these teachings increased sensitivity may only be attained at the expense of reducing sensing zone size along with undesirably increased clogging risk. Conversely, the approach of an increased sensing zone size to reduce clogging risk comes with the undesirable cost of reduced sensitivity and sensing consistency; a more energetic emitter or enlarged sensor mitigates these disadvantages to some degree but incurs increased component costs and energy consumption, both of which are undesirable especially for field applications without line power.
Thus, there remains a need for a cost effective pest monitor with high sensitivity, sensing consistency and minimized clogging risk along with low power consumption allowing the practicable use of remote battery powered pest sensors and sensor networks.